1. Field of the Invention
This invention relates to a disc driving device for recording and or reproducing information by rotating and driving an information recording medium which is formed into a disc, and particularly to a disc driving device suitable for an optical recording medium.
2. Description of the Prior Art
An optical disc driving device usually employs an auto-loading mechanism which introduces an information recording medium (hereinafter referred to as a disc) placed on a tray into the device along with the tray to provide recording and reproducing. A conventional optical disc driving device of this kind is shown in FIGS. 26 and 27. FIG. 26 is a sectional view showing the unloading state wherein a tray of a conventional optical disc driving device is moved out of the device body; and FIG. 27 is a sectional view showing the loading state wherein the tray is received into the device body.
Referring to FIG. 26, an optical disc driving device 1 is principally composed of a tray 3 which receives a disc 2 through a sub-tray 4 later described and which horizontally moves in and out of the device, a drive means (not shown) for moving the tray 3 into and out of the device, the sub-tray 4 on which the optical disc 2 is placed within the tray 3 and movable up and down, a means for lifting (not shown) the sub-tray 4, a turntable 6 provided with a raised portion 5 which is inserted into a central circular hole of the disc 2 to rotate and drive the disc 2, a motor for rotating and driving the turntable 6, a clamper 8 for pressing a portion in the vicinity of the central hole of the optical disc with respect to the turntable 6, an arm 9 for vertically turning the clamper 8, a pick-up 10 for recording/reproducing of the optical disc 2, a guide rail 11 for guiding the pick-up 10 in a radial direction of the optical disc 2, and a linear motor (not shown) for moving the pick-up 10 along the guide rail 11.
The above-described optical disc driving device 1 is operated in a manner as follows:
First, as shown in FIG. 26, in the unloading state, the optical disc 2 is placed on the sub-tray 4 within the tray 3. Then, the tray 3 is pulled into the device 1 by the drive means not shown, upon completion of which pulling-in, the sub-tray 4 moves down toward the turntable 6. During the downward movement of the sub-tray 4, the optical disc 2 remains placed on the turntable 6, and at the position slightly distanced from the optical disc 2 the sub-tray 4 finishes its downward movement. During the downward movement of the sub-tray 4, the clamper 8 is also moved down to press the optical disc 2 against the turntable 6.
Thus, the device assumes the loading state as shown in FIG. 27, whereby the optical disc 2 rotates and the pick-up 10 is moved in the radial direction of the optical disc 2 along the guide rail 11 by means of a near motor (not shown) to record or reproduce the optical disc 2.
Upon termination of recording or reproducing of the optical disc 2, the clamper 8 moves upward and the sub-tray 4 also moves upward whereby the optical disc 2 is released from the turntable 6 to project the tray 2 thus returning the unloading state shown in FIG. 26 to remove the optical disc 2.
In the above-described optical disc driving device, it is necessary to move the sub-tray 4 and clamper 8 upward and downward, and therefore various driving mechanisms are provided. Particularly, the sub-tray 4 has to be positioned away from the turntable 6 and pick-up 10 and to place the optical disc 2 in a stabilized fashion. In addition, they should be accommodated within the tray 2 including the lifting means, thus the mechanism becomes complicated. Moreover, the clamper 8 is moved up and down by the turning arm 9, and therefore a stroke occupying area thereof increases, and a complicated vertically turning mechanism is provided.
As described above, the sub-tray 4 and the clamper 8 causes the mechanism of the optical disc driving device 1 to be complicated and besides gives rise to a factor impairing formation of the device into a reduced thickness. This reduction in thickness is necessary in order that for example, an optical disc device is provided in place of a unit of a floppy disc device on a personal computer of a floppy disc encased type.